To develop an in vitro model of carcinogenesis of rat pancreas. Organ cultured embryonic rat pancreas will be treated with dimethylnitrosamine (DMN) and the alteration in its morphology and growth will be examined. Cell proliferation (DNA synthesis) will be studied by autoradiography and cell differentiation will be evaluated by the measurement of enzymatic activity (amylase, lipase and chymotrypsin). Morphological alteration (light and electron microscope) will be correlated with functional changes. Morphologically transformed explants will be implanted in vivo to evaluate their biological transformation.